Grinding machine for sharpening cutters and the like



Nov. 26, 1957 L. o. CARLSEN ETAL 2,81 ,166

GRINDING MACHINE FOR SHARPENING CUTTERS AND THE LIKE Filed Jan. 22. 1953 6 Sheets-Sheet 1 INVENTORS LEONARD O. CARLSEN BY A. JOHNSON 141? OLAF A T TORNEY Nov. 26, 1957 1.. o. CARLSEN El'AL 2,314,166

GRINDING MACHINE FOR SHARPENING CUTTERS AND THE LIKE Filed Jan. 22, 1953 6 Sheets-Sheet 2 wll 8 M a. 4-15 ---i .i 2

N QE W NM INVENTORS LEONARD O. CARLSEN BY OI AF A. JOHNSON ATTORNEY Nov. 26, 1957 L. o. CARLSEN ElAL 2,814,166

GRINDING MACHINE FOR SHARPENING CUTTERS AND THE LIKE Filed Jan. 22 1953 S'SheetS-Sheet 3 FIG. 3

FIG. 4

VENTORS LEONARD ARLSEN OLAF A. JOHNSON QM/Mm A TTORNE Y Nov. 26, 1957 L. o. CARLSEN ETAL 2,314,166

GRINDING MACHINE FOR SHARPENING CUTTERS AND THE LIKE Filed Jan. 22. 1953 6 Sheets-Sheet 4 i l I l i 1 I05 94 X O96 20 J O 1 1 Y INVENTORS I03 102 LEONARD o. CARLSEN 89-/ 404 BY OLAF A. JOHNSON ,8? K i 88 adv/Mm ATTORNEY Nov. 26, 1957 L. o. CARLSEN ETAL 2,314,165

GRINDING MACHINE FOR SHARPENING CUTTERS AND THE LIKE Filed Jan 22, 1953 6 Sheets-Sheet 5 I58 INVENTORS LEONARD O. CARLSEN OLAF A. JOHNSON Q; um

ATTORNEY FIG. 8

Nov. 26, 1957 1.. o. CARLSEN ETAL 2,81

GRINDING MACHINE FOR SHARPENING CUTTERS AND THE LIKE Filed Jan. 22'. 1953 e Sheets-Sheet e INVENTORS LEONARD O. CARLSEN OLAF A. JOHNSON ATTORNEY United States Patent GRINDING MACHINE FOR SHARBENING CU ERS, T E IKE Leonard O. Carlsen, Rochester, and Olaf A. Johnson, Irondequoit, N. Y., assignors to The Gleason Works, Rochester, N. Y., a corporation of New. York Application January 22, 1953 Serial No. 332,108 15 Claims. (Cl. s1- .-3s)

The present invention relates to improvements in a grinding machine, of the general type disclosed in Patent 2,224,959, granted to C. T. Galloway on December 17, 19.40, for-sharpening multi-bladed rotary cutters. and like grinding operations.

In the machine disclosed in that patent an abrasive wheel having a conical Working surface is passed back and forth. across the face. of. a cutter blade to sharpen it, the wheel being fed depthwise. of the face of the. blade on each pass. After a predetermined number of passes the wheel is. returned by the amount it hasbeen fed depthwise of the. ground surface, is withdrawn from the inter.- blade space of the work in which it has been operating, the Work isindexed to bring another face thereof into position to be gropnd, and the wheel is then advanced for a repetitipn of the grinding operation. This cycle is repeated until all the surfaces of the work have been ground, after which the abrasive wheel is automatically dressed, this being. accomplished by a greater withdrawal of the wheel than for indexing and a subsequent advance during which the wheel is passed over a dressing. ele-, ment. Prior to such advance. forv dressing, the. dressing element is moved into the path of the wheel and the. wheel is automatically fed, in a direction perpendicular to the grinding surface, to provide stock for, dressing.

According to the present invention the. machine is arranged to grind a chip-breaking lip on the tips of the blades of a cutter. The lips are ground to the same size even on cutters whose blades are of varying height around the periphery of the cutter. To. accomplish this a lipgrinding round is dressed on the edge of the abrasive. wheel, and, during the grinding operation, the advance or withdrawal of the wheel is controlled in accordance. with the height of the blade being ground. For forming the round on the wheel the dresser is moved depthwise of the wheel surface as the latter passes over the dresser. The actual motion of the dresser is effected by a hydraulic piston but is controlled by a movable stop which preferably takes the form of a rotatable cam. This cam is geared to the wheelcarriage, the cam being rotated in phase relationship with advance ofthe carriage. The mechanism for advancing the carriage also includes a hydraulic cylinder, and, during the grinding operation, the required advance orv withdrawal of. the car.- riage, to compensate for. differences in blade height, is effected by the cooperation of this cylinder andfa cam that is movcdconcomi-tantly with operation of. the index mechanism. by meansof. suitable gearing. That is, as the index mechanism operates to bring blades of different height into position to be ground, the cam is moved'to accordingly vary the position of thecarriage, so that lips of uniform sizeareground onthecutter blades. i

In order to prevent undue loads on the last-mentioned earn a valve isproyided to relieve the actuating hydraulic pressure, the valve being opened as the carriage approaches. the limit position determined byth cant. In practice two such cams are provided, one of them for use .in grinding the lips on the. blades and the .othercfor use. in grinding, the faces of the blades. This is desirable since the blades vary both in height and in radial distance from the center of the cutter.

The axis. of rotation of the abrasive wheel is inclined at an acute angle to the axis about which the wheel swings, the grinding profile of the wheel being perpendicular' to the latter axis. The non-grinding surface of the wheel may be plane, perpendicular to the wheels axis of rotation, and in order to provide stock for dressing the radius, the present invention provides a means to feed the wheel, prior to each dressing operation, in a direction perpendicular to its rotative. axis. To accomplish this the wheel support is fed along the axis of swing, and, concomitantly, in a direction perpendicular thereto, the resultant of the two feed motions being in the direction perpendicular to the axis about which the wheel rotates; The foregoing and other objects and advantages of the invention will appear from the following description made with reference to the drawings, in which:

Fig. 1 is a front elevation of the, machine with parts broken away and appearing in section;

Fig. 2 is a vertical sectional view through the side of the machine which includes the wheel carriage;

Fig. 3 is a detail view on a larger scale in the horizontal plane indicated by section line 3-3 of Fig. 1;

Fig. 4 is a vertical sectional view in the plane indicated by section line. 4 4 of Fig; 3;

Fig. 5 is a vertical sectional view in the plane indicated bysection lines 5--5 of Figs. 1 and 6; i

Fig. 6 is a vertical sectional view in a plane at right angles to that of Fig. 5 and as indicated by section line 6--6 of Fig. 5;

Fig. 7 is a detail end elevational view taken as indi cated by section line 7-7 of Fig. '6;

Fig. 8 is a diagram of the hydraulic system of the machine;

Fig. 9 is a schematic view illustrating relative motions of the abrasive wheel and the dressing element;

Fig. 10 is a diagram showing thedirections of wheel feed;

Fig. 11 is a view showing the relationship of the abrasive wheel to the cutter being ground; and,

' Fig. 12 is a view illustrating certain characteristics of one kind of cutter that may be sharpened on the machine.

The machine has a base 20 having horizontal ways 21 (Figs. 1 and 5) supporting a carriage 22 for motion to the "right or left in Fig. 1. As shown in Fig. 2 the carriage has an upright tubular part2? in which tubular part 24 of wheel head 25 is rotatably mounted. An abrasive wheel .W is carried by a spindle 26 that is journaled in the head 25 on anti-friction bearings, the spindle and wheel being rotated by a motor 27 through pulleys "28 and endless belt 29. The wheel head is adapted to oscillate about the upright axis of tubular parts 23 and 24 to pass the conical surface 31 of wheel W back and forth over the front face 32 of a blade 33 of cutter C when the slide 22 is advanced (moved to the left in Fig. 1 or to the right in Fig. 2)to bring the wheel into position.

The cutter C to be sharpened is secured to a work spindle 34 journaled in a head 35 that is adjustably grinding I mounted on the base 20. These adjustments in this case enable the cutter spindle to be brought to the proper height, angular position (wherein the axis of spindle 34 is perpendicular to the plane of Fig. 1), and lateral position along the spindle axis, for the particular cutters that In general these adjustments may be effected in the manner describedin aforementioned Patent No. 2,224,959, and they are not a part of the present invention.

-Mounted on the head 35 is an indexing device of the notched disc type, wherein the disc (not shown) "is ad vanced step-by-step by hydraulically operated means including a rack '36 (Fig. 8) reciprocated by a piston 37 operating in cylinder 38. On each stroke of the piston in one direction, upwardly in Fig. 8, the hydraulic means operate through a suitable ratchet device to advance the disc and the spindle 34 secured to it, to thereby advance the cutter C by one blade, while on the return or downward stroke of the piston and rack the cutter is not moved. By a suitable adjusting means interposed between the disc and the spindle 34, and operable by a knob 39 after a clamp 41 is first released, the spindle may be manually turned relative to the disc to bring the front face 32 of the first cutter blade approximately into the plane of surface 31 of the abrasive wheel. The indexing means and the index-to-spindle adjusting means are not parts of the present invention, the same being disclosed in aforementioned Patent No. 2,224,959.

The primary motions of Wheel carriage 22 are effected by a cam 42 and lever 43, and by a piston 44 operating in cylinder 45 (Figs. 1, 2 and 8). The cam is mounted on a shaft 46 rotatable in the base 20, and has peripheral cam track 47 in which there is engaged a follower roller 48 carried by the lever 43. The lever is fulcrumed to the frame at 49 and at its upper end is pivoted to a collar 51 that is confined between spaced shoulders on rod 52 of piston 44. The cylinder 45 is carried by a slide 53 which is movable on the wheel carriage 22 in the same direction that the latter is movable on the machine base. Slide 53 is held against carriage 22 by gibs 54 (Figs. 1 and 3), one of which is adjustable by a clamp screw (not shown) operable by a handle 55. By turning the handle the gib may be drawn down to remove excessive clearance between the slide and the carriage. Threaded to a nut integral with the cylinder slide is a screw 56 that the resulting reciprocation of the piston by lever- 43 will be effective through cylinder 45, slide 53 and screw 56 to reciprocate the carriage. This motion is employed to advance the wheel W into grinding position and to withdraw it to permit indexing the cutter C to bring a succeeding blade thereof into position for grinding. The cylinder 45 is shifted hydraulically, relative to piston 44, to impart a further or additional motion to carriage 22, to' pass the wheel W over a dressing element D at a time when the lever 43 has withdrawn the piston.

While the carriage is in its advanced or grinding posi tion, oscillation of the wheel head is effective to pass the wheel W back and forth over the face of a cutter blade. This oscillation is effected by a crank 58, Fig. 8, whose shaft 59, journaled in the carriage 22, is rotated by and in time with rotation of cam shaft 46 through a gear drive train indicated schematically in Fig. 8 by broken line 61.- The crank acts through a connecting rod 62 and an arm 63 to the wheel head 25 to oscillate the latter about the upright axis of its tubular part 24. The ratio of the drive train 61 is such that the wheel W makes several passes back and forth across the blade being ground while the carriage 22 is held stationary in its advanced position, the cam follower 48 at this time being in a dwell in cam track 47.

As the wheel is oscillated past each cutter blade face it is fed downwardly to grind successive increments of stock from the blade on successive passes, and, after the last pass, it is moved upwardly by an amount equal to the total down feed. Different rates of down feed are feed cams 64 and 65 are provided. These cams are on a shaft 66, Fig. 2, journaled on anti-friction hearings in a sleeve 67 that is slidable, in the direction of the shaft axis, in a bracket 68 that is a part of carriage 22. The shaft 66 is splined to cam shaft 46 and is movable axially, together with sleeve 67, upon rotation of a. shaft 71 which has teeth 69 formed thereon meshing with annular rack teeth 70 provided on sleeve 67. Shaft 71 is journaled in the carriage and is operated by hand lever 72. By this means either one of earns 64 and 65 may be engaged beneath a cam follower 73 that is connected by key 73' to a bearing head 74. The cam follower is adapted for vertical adjustment in the head and for this purpose is threaded to a screw 75 that is rotatably supported by this head. The head is held by a key 74' against rotation in part 23 of the carriage and is vertically movable therein. Bearing rings 76 between a flange on the head 74 and the bottom of tubular part 24 of the wheel head 25, provide the vertical support for the latter. On each complete revolution of cam 64 the parts 73, 75, 74, 76, 24 and first move downwardly as a unit, gravity causing them to follow the cam, and then they are lifted by the cam to their original position. To compensate for stock worn or dressed off of wheel W the parts 74, 76, 24 are lowered relative to follower 73 by rotating the screw 75. This rotation is effected automatically, as a prelude to each wheel dressing operation, by means including a piston 77 (Fig. 8) operable in a cylinder 78, a ratchet pawl 79 adapted to rotate a ratchet wheel 81 one step for each reciprocation of the piston, and universal jointed shafting 82 (Fig. 2) connecting the wheel 81 to a bevel pinion 83 meshing with a bevel gear 84 on screw 75. As shown, the pinion 83 is journaled for rotation in the bearing head 74.

For dressing the active surface of the wheel, the diamond D and its mounting 85 are supported on a dressing element carrier comprising a piston rod 86 (Figs. 5 and 8) on whose reduced lower end 87 a piston employed for rough and finish grinding, and therefore two 88 is mounted for limited vertical motion, and the piston beingslidable in an upright cylinder 89 mounted on the machine base 20. When the piston is lowered the diamond is lowered out of the path of feed motion of the wheel; when raised to its upward limit position, abutting the upper wall of the cylinder 89, the diamond is po-' sitioned at a level slightly below that of the surface 31 to be dressed on the wheel W. The final upward motion of the diamond into dressing position is accomplished by hydraulic pressure on the bottom of rod 86, the reduced end portion 87 of the rod sliding within the piston 88.

In order that the axis of the wheel will always lie in theacts upon a fiat 91 on an enlarged portion of crank shaft.

59 to so align the crank 58 that the wheel is held in this centered position. The bar is actuated by a piston 92 contained in a cylinder 93 mounted on the carriage 22.

For dressing the round on wheel W needed to grind the chip-breaking lip on the cutter blades, the present invention provides a cam 94 (Fig. 5) for limiting the upward travel of piston rod 86 and dressing element D and for effecting a down movement of them in time with the in-feed orv advance of the carriage 22 that is caused by the piston and cylinder 44, 45. For this purpose a bar 95 secured to the cylinder 45, and guided for reciprocation in a bracket 96 on the base 20, is provided with rack teeth 97 meshing with a pinion 98. The latter is rotatable in bracket 96 and is connected by gear pairs 99 and 101 to the shaft 102 of the cam 94, this shaft being journaled in a sleeve 103 supported between bracket 96 and cylinder body 89. The cam engages a follower pin 104 on rod 86.: As cylinder 45 moves to the left (Fig. 6), carrying with it the carriage 22 and wheel W, the gearing 99, 101 rotates the cam which is so shaped that the follower 104, and hence also the diamond, is lowered at agradually diminishing velocity during theinitial portion of the wheel dressing stroke and is then held at the same level during the remainder of'the dressing stroke. The relative motion of the diamond and the wheel is as shown in Fig. 9, where, for thepurpose of illustration the horizontal. motion isshown as being applied to the diamond ratherlthan, as in actuality, to the wheel. During the initial horizontal dressing motion through distance S, the diamond D is lowered tosuccessive positions D and D" to produce the round R on the edge of the wheel. During .theremainder of the dressing stroke, designated ST, the diamond remains at the constant level indicated at D" and D", thus dressingthe straight profiled surface 31 on the wheel. Whenit is desired to dress the wheel without the round R, the wheel W is adjusted outwardly (to the right in Fig. 1) relative to carriage 22, by manually turningthe screw 56 through means to be hereinafter described, so that the edge of the wheel does'not contact the diamond. during the dressingstroke of the carriage until after the down motion D to D" in Fig.9 has-been completed. As shown in Fig. 5, a key 105 seating in a keyway in the diamond supporting rod 86 holds the latter against rotation.

Because of the inclination of the wheel axis, it is necessary to feed the wheel both vertically and horizontally to compensate for stock worn or dressed off of the face 31. Thus asthe surface 31 is dressed back to 31' (in Fig. it is necessary to advance the wheel relative to carriage 22 by the horizontal distance H concomitantly with lowering. of the wheel by the vertical distance V, in order that the amount of stock at the edge of the wheel available for forming the radius R will remain constant. To accomplish this an intermittent feed means for the screw 56 is provided, this means operating simultaneously with. the means 7781, heretofore described, which effects the vertical feed of the wheel. The feed means for screw.56,.shown in Figs. 3, 4 and 8, comprises a piston 106 reciprocable in a cylinder 107 secured to bracket 57, a pawl 108 pivoted at 109 to head 111 on the rod of piston 106,. and a ratchet wheel 112 which is advanced by one tooth on each reciprocation of pawl 108 by jlz'piston .106, the stroke of piston being limited by a stop 113 engageable by the head 111; The ratchet wheel is mounted'on a shaft 114 that is journaled on anti-friction hearings in bracket 57 and is connectedby bevel gears 115 with screw 56. The ratchet wheel 112, gears 115 and screw 56 are so proportioned that on each reciprocation of the piston 106the slide 53, and hence also the wheel W, is automatically advanced relative to carriage 22 by a distance that is related to the vertical motion of follower 73 relative to head 74 (Fig. 2) effected by each reciprocation of piston 77, in the ratio of H to V (Fig. 10). The screw 56 may also be rotated manually, by a wrench applied to the outer-end of shaft 114. If this is :to involve retrogression of ratchet-wheel 112, the pawl 108 is first lifted by cam 116 which may be rotated by a handle 117.

For controlling the inward limit position of the slide 22 and wheelW there are provided cams 118 and 119 (Figs. 6 and 7), and a follower or stop element 120 on the rod 95. The cams are secured to a shaft 121 journaled for rotation in a bracket 122 that is secured to the base 20. Also secured to shaft 121 is a gear 123 meshing with a pinion 124 on a countershaft 125 supported by the bracket 122. A pinion 126 rotating asa unit with pinion124 meshes with a gear 127 on the cutter spindle 34. The gearing v123, 124, 126, 127 is of 1:1 ratio, so that the cams 118, 119 are rotated one turn for each complete turn of the cutter spindle. The follower 120 has a tip 128 adapted to ride on the surface of either one of the cams, cam 118 in Fig. 7. Upon loosening of a set screw 129 which holds the follower 120-to rod 95, the follower may be removed and installed in inverted position, so that the tip 128 may ride on the other cam, 119.

Thefunction of cams 118, 119 and follower 120 may be explained with reference to Figs. 11 and 12. The

6 roots of the blades 33, of the particular cutter shown, lie along one spiral 131 and the tips along a spiral 132 of somewhat greater lead, the height H of the first blade to be ground. (assuming that the cutter is indexed counterclockwise in Fig. 12 during the sharpening operation) being less than height H" of the last blade. In order to sharpen the faces 32 to substantially their full height, the wheel W (the broken line position thereof in Fig. 11)

must be successively moved outwardly to successive positions to the right in Figs. 1 and 11, as successive blades are ground. This is accomplished -by the follower tip 128 engaging the cam 119 whose active face is a spiral of the same lead as spiral 131. Similarly, in order to grind the lips to the same height on all of the blades,

the position of the edge of the wheel must be retracted 118 or 119) under. a relatively light load in order to minimize wear. To accomplish this a reliefvalve 134,- Figs. 6 and 8, is arranged between the cylinder chamber at the left of piston 45 and an exhaustpassage 135 leading to the hydraulic sump. The stem of the valve is guided in a bushing on an apertured plate 136 secured to the headof the cylinder 45, and a spring 137 backed by this plate urges the valve against an annular seat 138. The valve is opened, to relieve the fluid pressure in the adjacent cylinder chamber, by a rod 139- The latter is slidable and rotatable in a bore through the rod 95, and its tip 141 projects slightly beyond the tip 128 of cam follower when valve 134 is seated. As appears iti- Fig. 7, the tip of the rod is substantially semi-circular in cross section so that it can contact only the same one of cams 118 and 119 that the follower tip 128 contacts. A set screw 142 engaging. a fiat on the rod, causes the latter to turn, to become engageable with the other one of cams 118, 119, when the follower 120 is invertedfor the same purpose. The action of the rod 139 and valve 134 is such that as the cylinder 45 and carriage 22 advance under hydraulic pressure reacting against piston 44-the tip of the rod will engage the cam, 11 8 or 119, before the follower tip 128 does so; and accordingly the valve 1341s opened, thus relieving the hydraulic pressure in the'cylinder chamber so that the follower will come into contact with the cam, and be held against it during the ensuing grinding operation, by a reduced pressure.

Reference will now be made to several parts of the machine shown in Fig. 8, which, while not parts of the present invention, are necessary to the operation of specific embodiment shown. A pump 143 operated by a motor 144 draws hydraulic fluid from a sump 145 and discharges it under a pressure controlled by a relief valve designated V-REL. The dressing function of the machine is controlled partially by a control valve 146 and a safety. valve 147, the casings of both valves being mounted on the base 20. Valve 146 is shifted by a lever 148 that is fulcrumed on frame 20 and is moved by adjustable abutments 149 and 151 on the cylinder 45 (see also Fig. 6). Valve 147 is operated by a cam 152 (see also Fig. 2) on shaft 46 against which the valve stem is held by a spring 153. The cutter indexing function is controlled by a similar valve 154 whose stem is held by a spring 155 against another cam, 156, on the shaft 46.

The machine is further controlled by a manually controlled spring-backed valve 157 having a spring actuated latch 158 that is released by a solenoid 159, the latter being controlled by an automatic stop mechanism (not shown); This mechanism, operated by a cam 161 on 7 shaft 46, is manually set for the number of blades on the cutteri'and} acts to shut ofijthe machine whenfacorresponding number of machine cycles have been completed. The automatic stop mechanism operated by cam 161 may be of the type described in Patent No. 2,005,142, granted toM. 'HqHill on June 18, 1935, while the means by which the stop mechanism controls the solenoid 159 may be of the kind described in aforementioned Patent No. 2,224,959. A manually operable shut-off valve 162 has an extension which .in one position thereof is 'engageable under a colla'rl63 on the stem of valve 157 to prevent movement of the latter.

To operatethe machine, a cutter C to be sharpened is first mounted on the s'pindle' 34 and the latter is adjusted by turning knob 39'to bring the first cutter blade into position for grinding, substantially that shown in Fig. l. The lever 72 is positioned to bring roughing feed cam 64 beneath follower 73, the follower'120 is positioned to contact cam 119, and the pump motor 144 and the wheel motor 27 are started. With valves 1'57 and 162 in the positions shown in Fig. 8, fluid is discharged under pressure from pump 143 into'line 164, applying pressure via line 165, valve 157 and line 166 to the right chamber of cylinder 45, thereby holding the carriage 22 fully withdrawn inasmuch as at this time the cam 42 is stopped in aposition wherein piston 44 is in its limit position to the right (Fig. .1). Pressure is also applied through lines 164 and 167, valve 154, andline 168 to the bottom chamber of index cylinder'38 holding the index rack 36 in its uppermost position. Pressure is also applied through line 164, valve 146,- line 169, valve 162, and line 171 to the right chamber of cylinder'93, thereby holdint the centering bar 90 operative to align the wheel head 25 foridressing. From,line 171 pressure is also effective via line 172. valve 147. and line 173 to the bottom chamber of'cylinder 88, holding the element D in its elevated or dressing position. From line 173 pressure is also applied by way of lines 174 and 175 to hold the wheel vertical and horizontal feed pistons 77 and 106 to the right (in Fig. 8).

v Valve 157 is now moved downwardly by manual pressure, and is retained in this'position by latch 158. Pressure from line 165 is now applied through valve 157 and line 176 to the left chamber of cylinder 45, While fiuid may exhaust from the right chamber of the cylinder via line 166, valve 157, and lines 177 and 178 to the sump. Accordingly the cylinder 45 moves to its limit position to the left relative to piston 44, and in doing so carries the wheel W across the diamond D, thereby dressing the surface 31. As before described, if the round R is wanted on the wheel, then during the initial portion of this dressing stroke the round is formed by lowering of the diamond by action of rack 97, gearing 98, 99, 101, cam 94 and follower 104.

Toward the end of the dressing stroke, stop 151 engages and moves lever 148, shifting valve 146 to put line 169 on exhaust by way of lines 170, 180 and 178 and to connect pressure line 164 to line 179 which communicates through valve 162 with line 181 to the upper chamber of cylinder 88, so that the piston 87 and dresser D are lowered, and to line 182 leading to the left chamber of cylinder 93 so that the bar 90 is retracted (line 171 being on exhaust via line 169). At the same time lines 183 and 184 are put on pressure through line 182, so that the vertical and horizontal ,feed cylinders are moved to reset their respective ratchet pawls 79 and 108.

The main drive motor may now be started, operating through drive 61 and crank 58 to oscillate the wheel head 25, and also to rotate the cam shaft 46. During the initial part of suchrotation the cam 42 acts through lever 43 to move the piston 44 forwardly, the column of fluid ahead of the piston, i e., to the left of the piston in Fig. 8, advancing the cylinder 45 untilarrested by the action of cam 119, rod 139 and cam follower'120, as hereinbefore described. As the wheel W now oscillates over the face 32 of the first cutter blade, "th'e cam 64, Fig. 2.; is rotating 2 to lower the wheel head, so that on each pass of the' wheel cam 156 allows the spring 155 to reverse valve 154,'apply- 5 ing pressure from line'167'to li ne185 and past check valve vj 186 to the upper end of cylinder 38 and putt'ng the lower .j and of the cylinder on exhaust to the sump through lines i 168, 188, 180 and'1'78. This lowers the indexing piston 37, resetting rack 36 for a' subsequent indexing stroke.

Toward the conclusion of [the first revolution of cam, shaft 46 the cam 42 actsthroug'h lever 43 to withdraw' piston 44, cylinder 45 and slide 22 enough to permit in f dexing of the cutter.- Then such indexing is effected by f the lobe of cam 156' again reversing valve 154 to apply pressure through line 168 and check valve 187 to the bot tom chamber ofc ylinder 38 and'put the upper chamber on exhaust via line "185, so 'that' piston 37 and rack 36 are moved upwardly to advanceth'e, cutter C by one blade. The check valves186 and '187, are of the metering type which limit butdo notstop't'he fiow of exhaust fluid past them, thereby slowing the motion of piston 37 at the end of each stroke. 7

The cam shaft 46 now begins a second revolution, and the grinding cycle is repeated until all the blades of the cutter have been sharpened. Then the automatic stop! mechanism, which is actuated by'cam 161, stops the feed? motor with the'cam 42 h'oldingthe piston 44 retracted and the cams'l52 and '156 in'the posi tion shown in Fig.' 8.' Also the solenoid 159' is energized by the action of the automatic stop mechanism to thereby release latch 158. Valve 157 is thereupon spring-'r'eturnedto its upper 'position. Pressure is applied via lines 164 and 165, valve 157 and line 166 to the right chamber of cylinder 45, and'the left chamber of the latter is put on exhaust through line 176, valve 157 and line 178.

The cylinder 45 and the wheelcarriage 22 are thereby fully withdrawn, and toward the end of the cylinders stroke the stop 149 acts through lever 148 to restore valve 146 to the' position shown. This applies pressure through line 169, valve 162 and line 171 to the right end of cylinder'93, while the left chamber of the cylinder is placed on exhaust via line 182, valve 162 and line 179. Hence the bar is moved to its operative position by piston 92, thus centering the wheel head, if it has not stopped exactly in this position, and acting through drive train 61 to bring cam 152 into the position wherein valve The lever 72 may now be shifted to bring finishing cam 65 instead of roughing cam 64 into operative position beneath follower'73; and the sharpening cycle described above then repeated to finish grind the surface 32 of the cutter blades. At the conclusion of this second cycle, the cam followerj may be inverted so that the tip 128 thereof, and the'rod 139, will engage the cam 118. The cutter is advanced slightly by turning the knob 39 as hereinbefore described, to thereby rotate the surface 32 of the blade in grinding position through an angle representing the depth to which it is desired to grind the lips L. Ordinarily this depth may be on the order of one hundredth of an inch. Then the operating cycle of the machine may again be repeated, thistime forming the lips L. At the end of each com lete cutter sharpening cycle the machine stops with the dresser D in its elevated position and the wheel locked What 90 in its central position. In order to facilitate replacement of wheel W the dresser maybe lowered and the wheel head swung to one side by manually shifting valve 162 to the left of the position shown. Thisapplies pressure from line 164 through line I 169, valve 162 and line 181't'o the upper chamber of cylinder 89 and via, line 182 to the leftchamher of cylinder 93,

while theright chamber of cylinder 93 is putonexhanst,v throughv line 171, valve 162 (including line 189), linexl79,

It will be understood that whilelhe-machine described t and illustrated represents a preferred embodiment of the:- inventive principles involved, these principles may be in.v corporated in other physical forms andv arrangements withv out departing from the-spirit of .theinvention or from the scope of: the appendedclaims.

What is claimed is:

1. A machine for grinding multi-bladedarotary cutters and like work having multiple surfaces tobeground, comprising a workspindle, a spindlethaving a grinding wheel thereon, asupportfor the wheel spindle arranged for movement to pass a surface of the wheel back and forth across a surface of a workpiece on the work spindle, a carriage for'the wheel spindle support movable toward and away from the work spindle supportmneans for holding the wheel spindle support in a predetermined position on the carriage during at least one of said carriage movements, a dressing element to engage said surface of the wheel during the last-mentioned-movement, and means operable instimed relationshipwith the carriage for moving thedressing element depthwiseof said surface of the wheel during a portion only of said last-mentioned movement and for holding it stationary during anadjacent portionof. said last-mentioned movement to thereby dress on..the wheel an edge round and an adjoining straight profile.

2. A machine according to claim 1 in which the means for moving the dressing element depthwise includes a cam and gearing connecting-it tothe carriage for movement in phaserelationship therewith;

3. A machine for grinding multi-bladed rotary cutters and the like, comprising a work spindle, a spindle having a grinding wheel thereon, a support for the wheel spindle arranged for swinging motion, about an axis inclined at an acute angle to the axis of the wheel spindle, to pass a surface of the wheel across a surface of the work, a carriage movable toward and away from the work spindle in a direction perpendicular to the axis of swinging motion,

a slide movable relative to the carriage in the same direction that the latter is movable, the wheel spindle support being movable upon the carriage along the axis of said swinging motion, index means to periodically rotate the work spindle to bring the surface of the work successively into position to be ground, actuating means to swing the wheel spindle support; means operating in phase relationship with said actuating means to withdraw the slide and the carriage in unison, means to operate the index means when the carriage is withdrawn, other means to further withdraw and advance the slide and the carriage in unison for dressing the wheel, means operable upon each such further withdrawal to feed the wheel spindle support relative to the carriage along said swinging axis and to concomitantly feed the carriage relative to the slide, means for holding the wheel support in a predetermined position on the carriage about the axis of swinging motion at least during said advance, a dressing element and means for moving it depthwise of the surface of the wheel during a portion only of said advance of the carriage and for holding the dressing element stationary during an adjacent portion of said advance, to thereby dress on the wheel an edge round and an adjoining straight edge.

4. A machine comprising a frame, a work spindle support and a tool support on the frame, a work spindle journaled for rotation in the spindle support, a movable carriage mounting one of said supports on the frame, means including a fluid pressure piston and cylinder for moving the carriage to effect relative advance and retraction of said supports, indexing means operable to angularly advance the work spindle upon such relative retraceach. indexing operation to limit the relative advance of hydraulic pressure supply system for the piston andcylin-- der, to urge the carriage into the limit position thereof wherein the follower engages the cam means, a-valve in v said system for relieving the pressure on the piston-and cylinder, and an actuator for the valve arranged toube operated by engagement with said cam means, to open the valve during the approach of the follower into engagement with the cam means.

7. A machine for grinding multi-bladed rotary cutters and like workhaving multiple surfaces to be ground, comprising a base, a work spindle support on the base, awheel spindle having a grinding wheel thereon, a support journalingthe Wheel spindle, a carriage for the wheel spindle support movable on the base toward and away from the work spindle support, a dressing element to engage the surface of the wheel during one such movement .of the carriage, a carrier for the dressing element movable on the base, and means for moving the carrier to shift the dressing element depthwise of said surface of the wheel during said .one movement of the carriage.

8. A machine for grinding multiple-bladed rotary cutters and like work having a multiplicity of angularly related surfaces to be ground, comprising a frame, a work support and a grinding wheel support mounted on the frame, a work spindle journaled for angular motion in the Work support, a grinding wheel mounted for oscillation on the grinding wheel support whereby such wheel may have a stroking motion relative to Work on the work spindle, a carriage for one of said supports mounted for movement on the frame to advance and Withdraw respectively toward and away from the other support, indexing means for intermittently effecting angular advance of the work spindle to bring successive angularly related surfaces of the work into position to be ground, means operating intermittently in time with the indexing means, to withdraw the carriage prior to indexing and to advance it subsequent to indexing, and intermittently movable stop means for the carriage comprising a cam and a drive therefore operating concomitantly with said indexing means, to vary the position to which the carriage is advanced subsequent to indexing.

9. A machine according to claim 8 in which there is gearing connecting cam to the work spindle for rotation in time therewith.

10. A machine according to claim 9 in which there is a cam follower movable with the carriage and means including a hydraulic piston and cylinder, and a pressure, supply system therefor, to urge the carriage into the position thereof wherein the follower engages the cam, a valve in said system for relieving the pressure on the piston and cylinder, and an actuator for the valve arranged to open the latter during the approach of the follower into engagement with the cam.

11. A grinding machine comprising a base, a carriage for a rotary grinding wheel reciprocable on the base, a dressing element carrier movable relative to the base between an advanced position wherein the dressing element is in the path of the wheel and a retracted position wherein the element is out of said path, yieldable means for effecting movement of the carrier between. said advanced and retracted positions',-;and movable stop means engageable by the carrier during advance thereof to efiecting movement of the carrier comprises a hydraulic system controlled by said means for actuating the-can,

riage, for effecting advance of the carrier into engagement with said stop means at the end of one stroke of the actuating means and retraction of the carrier at the end of the return stroke.

14. A grinding machine comprising abase having a work support thereon, a carriage and a grinding wheel spindle support mounted thereon, the carriage being mounted on the base for movement thereon to carry a wheel on the spindle toward and away from work on the work support, the spindle support being arranged to swing upon the carriage about an axis perpendicular to the direction of carriage motion and inclined at an acute angle to the axis of the wheel spindle, a wheel dressing element on the base, means including a slide movable in unison with the carriage to reciprocate the latter on the base to carry the wheel over the dressing element, and means operable concomitantly with each such reciprocation of the carriage to feed the wheel support relative to the slide in a direction perpendicular to the wheel spindle axis in the plane in which the axis of swing moves as the carriage reciprocates.

"15. "Agrinding machine comprising a base having aj worksupport thereon, a carriage and a grinding wheel spindle" support mounted thereon, the carriage being mopnted on the base for movement thereon to carry a wheel on the spindle toward and away from work on,

the work support, the spindle support being arranged to swing upon the carriage about an axis perpendicular to the direction of carriage motion and inclined at an acute I angle to the axis of the wheel spindle, a wheel dressing element on the base, means including a slide movable in unison with the carriage to reciprocate the latter on the base to carry the wheel over the dressing element,

and means operable concomitantly with each such reciprocation of the carriage to feed the wheel support relative to the carriage in the direction of the axis of swing of the wheel spindle support and also to feed the carriage relative to the slide in the direction of carriage motion on the base.

References Cited in the file of this patent UNITED STATES PATENTS 1,884,985 Van Hamersveld Oct. 25, 1932 1,982,050 Gleason et a1. Nov. 27, 1934 1 2,005,822 Burrell June 25, 1935 r 2,224,959 Galloway Dec. 17, 1940 2,304,970 Turner Dec. 15, 1942 2,348,354 Miller May 9, 1944 2,423,943 La Pointe July 15, 1947 2,424,271 Galloway July 22, 1947 1 2,473,741 Wilder June 21, 1949 2,584,003 Engelmann Ian. 29, 1952 FOREIGN PATENTS 684,838 Germany Dec. 6, 1939 France Oct. 12, 1942 1 

